1. Field of the Invention
One or more embodiments of the present invention relate to a color reproduction technology, and more particularly, to a white balancing method, medium, and system.
2. Description of the Related Art
Though natural Light is typically thought of as being white, in actuality the light may have an abundance of one or more wavelengths resulting in the overall light having a peculiar color called a color temperature, expressed in Kevin (K). In general, since the human beings' visual ability automatically adjusts for such minor discrepancies, the human beings' cognitive difference for the colors is very insignificant even though light of a particular color temperature may be illuminated. However, image pick-up devices, such as a camera or a camcorder, sense colors, in which color temperatures are reflected, as they are. Accordingly, if an illuminant is changed, images taken by the image pick-up device are tingled with different colors.
For example, since the color temperature of sunlight around noon on a sunny day is considered to be high, the image taken by an image pick-up device will appear bluish on the whole. By contrast, since the color temperature of the sunlight just after sunrise or just before sunset is considered to be low, the image taken by the image pick-up device will appear reddish on the whole.
An auto white balancing (AWB) technique proposed to solve this problem compensates for distortions of the color tone of the image if the image is deflected toward any one of red (R), green (G), and blue (B) components depending upon its color temperature.
In one example, an image pick-up device discussed in Japanese Patent Unexamined Publication No. 2002-290988, divides an object into a plurality of regions, detects chromaticity in every region having a luminance higher than a threshold value, and calculates a gain value to perform white balancing based on the detected chromaticity.
However, such white balancing techniques have problems in that it is difficult to perform a consistent color reproduction in accordance with the color or dimension of an object existing in the image even though the image is taken under the same light source or illuminant.